The present invention relates to a camera system having interchangeable lenses, wherein some of the lenses have an aperture preset operation member and some of the lenses do not have an aperture preset operation member.
Various control modes are known for controlling exposure during photographic operation. For example, such known modes include a manual mode (M mode), a shutter speed priority mode (S mode), an aperture priority mode (A mode), and a program mode (P mode). The manual mode (M mode) allows a photographer to freely set both shutter speed and aperture value. The shutter speed priority mode (S mode) allows the photographer to set the shutter speed while the camera automatically sets the aperture value. The aperture priority mode (A mode) allows the photographer to set the aperture value while the camera automatically sets the shutter speed. Finally, in the program mode (P mode) the camera automatically sets both shutter speed and aperture value. Of these modes, both the M mode and A mode require operational members, e.g., switches, dials and the like, to allow the photographer to set the aperture value.
For a camera system having interchangeable lenses, there are two methods by which an aperture value may be set. First, the aperture can be set using an aperture ring on the lens. Second, a setting member on the camera body may set the aperture value. In general, camera systems are standardized across the range of lenses and use one of the noted methods. In other words, any one camera system exclusively uses one of the above-noted methods. Japanese Laid-Open Patent Publication Number 63-123028 discloses a technology that employs both methods for use with lenses having an aperture ring. In general, the '028 publication is directed to a system identifying whether the mounted interchangeable lens is aperture controllable and switching to the appropriate mode. Accordingly, the aperture value is set either by an aperture ring on the interchangeable lens or by the camera's aperture setting device.
To meet the diverse needs of users, camera bodies that are capable of setting the aperture value while using interchangeable lens without an aperture ring are being developed. Additionally, traditional camera bodies that are capable of setting the aperture value using an aperture ring on the mounted lens continue to be developed. Depending on the combination of camera bodies and interchangeable lenses, some functions may be redundant, or one function may interfere with another function. The camera system, as a whole, may become too complicated and confusing for users if these functions are available at the same time or cancel each other out.
The current solution is to design a camera body that accommodates only one type of interchangeable lens, so as to prevent complicating the camera system and to simplify handling. However, it is preferable to allow multiple types of interchangeable lenses to be mounted on a camera body so as to increase compatibility of the various interchangeable lenses across various existing and future camera systems.